Frequency Offsets in RFX 2400

I’m an italian student and I’m working on OFDM system of GNUradio
I have a problem.
I’m a couple using RFX2400 to transmit a data stream but I can’t receive
I checked the frequency offset and I found that the frequency offset is
10-15 kHz.
I think this value is very hight. If I change the frequency of receiver
with such value I receive packets.
I was thinking about inserting it direcly in the code, but it is the
result of
an average of a set of measuremnt and it isn’t an accurate value.
Moreover, with a different equipment, it will easyly be different.

Could you help me?
Thank you a lot.